三坐标测量技术在汽车制造业中的应用

大量的三坐标测量机用于汽车产品质量控制,提供了一种快捷方便的检测手段。为正确进行测量和分析,许多规范和必要的辅助工具也是必须的。     

A functional-to-behavioural transformation framework for specification and design of manufacturing systems

To maximize the productivity, quality and safety of operators, design and dependability analysis tools must be integrated as soon as possible in the lifecycle of automated manufacturing systems (AMS). As a concurrent approach, the structured analysis and design technique (SADT) can be efficiently used for such integration. SADT is a graphic notation for system specification and requirement analysis that is well adapted to describe the functions and their interconnection in a manufacturing systems. In spite of its advantages, SADT is limited by the lack of a formal foundation, which makes it necessary to extend it by a mathematical behavioural model such as the Petri net. This article first proposes an approach for the automatic generation of the Petri net model corresponding to SADT specifications, thus allowing a direct simulation of the SADT model to validate its behaviour. The complexity and non user-friendly interface of such a Petri net have led us to propose a temporal SADT whose primitives represent abstract types for the underlying Petri net model. This temporal SADT has the merits of both the SADT and Petri nets, since it adds to the user friendliness of SADT, the foundation of Petri nets.     

Training in coordinate measurement using 3D virtual instruments

Coordinate metrology is a subject that has evolved driven by two important vectors: hardware and software development. At present, most 3D measuring software offer features for offline programming of the Coordinate Measuring Machines (CMM). A few software solutions enable the simulation of both the CMM and other elements involved in the measuring process, such as the human operator or an automated system for loading and unloading the measured parts. The paper presents the features and advantages offered by Delmia V5 for simulating a complete measuring environment encompassing: the CMM, the human operator, a robot or automated system for manipulating the parts. The simulations developed represent a powerful learning tool that can complement existing models for CMM training.     

基于多传感器集成的三坐标测量机自动检测规划系统研究

为了充分发挥多传感器集成的优势，提高检测自动化水平，提出了该环境下三坐标测量机自动检测规划系统的体系结构。构建了专家规则库来制定检测策略，选择检测设备。重点分析了接触式测量检测规划的流程，提供了零件定位、测点自动生成等模块的解决方案。讨论了光学自动检测规划的要点。通过中性文件的使用和映射，实现了CAD与三坐标测量系统的集成，从而为产品的自动检测和质量控制提供了保障。     

Direct Volume Rendering Methods for Cell Structures

The study of the complicated architecture of cell space structures is an important problem in biology and medical research. Optical cuts of cells produced by confocal microscopes enable two‐dimensional (2D) and three‐dimensional (3D) reconstructions of observed cells. This paper discuses new possibilities for direct volume rendering of these data. We often encounter 16 or more bit images in confocal microscopy of cells. Most of the information contained in these images is unsubstantial for the human vision. Therefore, it is necessary to use mathematical algorithms for visualization of such images. Present software tools as OpenGL or DirectX run quickly in graphic station with special graphic cards, run very unsatisfactory on PC without these cards and outputs are usually poor for real data. These tools are black boxes for a common user and make it impossible to correct and improve them. With the method proposed, more parameters of the environment can be set, making it possible to apply 3D filters to set the output image sharpness in relation to the noise. The quality of the output is incomparable to the earlier described methods and is worth increasing the computing time. We would like to offer mathematical methods of 3D scalar data visualization describing new algorithms that run on standard PCs very well. SCANNING 34: 367‐377, 2012. © 2012 Wiley Periodicals, Inc.     

Cutting tool strategies for multifunctional part configurations: Part I—analytical economic models for cutting tools

The optimisation problem of multifunctional cutting tools, including multistep and combination tools, has been investigated. The tools' concepts for their physical understanding are discussed in order to provide the necessary background for the reader. Since they are not available in the literature, the necessary mathematical models for the optimsation are analysed based on constant tool speed (rpm), constant surface speed and variable speed or feed for each tool step and/or function. The integration of the mathematical models in optimisation schemes results in an analytical design tool for modelling and simulation of the advanced multifunctional tools in an early part processing stage that refines the process and tooling approaches while determining the sensitivity of these tools to the performance and production cost of individual machines. The aforementioned problem has been theoretically analysed here, while heuristic optimisation algorithms for determining the optimum cutting speed(s) and feed(s) for the multifunctional tools are presented in Part II of this paper. Experimental results and analytical examples which demonstrate the effectiveness and advantages of the proposed approach utilising the described mathematical models are presented in Part II.     

Development of a parameterized mechanical model of a chisel-edge grating ruling tool

The parameterized mechanical model is proposed to optimize chisel-edge grating ruling tool parameters, eliminate corrugated grating lines, improve surfaces roughness of blaze plane, and reduce complex fabrication works such as step-by-step modification of tool guide angle. A mathematical model of force and torque between the diamond tool and the metallic film during the ruling process is deduced to realize optimized diamond tool geometrical parameter design. Then, grating ruling experiments are performed by tools with different guide angles of 75°, 95°, 115° and 135°, respectively. The experiments results agree well with the theoretical calculation value of force and torque. Experiments show that our proposed method is an effective way to solve the corrugated line and fluctuating problems on grating grooves, and can avoid complex and time-consuming technical operations such as step-by-step modification of tool guide angle. This illustrates the significance of our model for practical applications in the ruling of high-performance gratings.     

渐开线齿轮齿根应力分析

提出了基于任意转角位置的渐开线齿轮齿廓数学模型的齿根任一点局部应力的折截面法计算数学模型,并验证了该数学模型中曲率半径计算公式的准确性.运用该数学模型实现了不同的刀廓构成参数和齿轮齿数对齿根最大应力、应力分布影响的数值分析.其计算结果将为渐开线齿轮设计、参数优化选择等提供参考数据,同时为齿根应力数值分析提供了新的数学模型.     

RETRACTED ARTICLE: Study on the expression specifications of geometrical products for function, design, manufacture and verification based on the improved GPS language

For the design, manufacture and verification, a consistent geometrical model for the product functional geometry is required. In this paper, we analyze the relation of the geometrical model with the design, manufacture, and verification of the geometrical product. Based on the improved GPS language, the new concepts and mathematical tools for the geometrical specifications are defined. A surface model defined in the new GPS can be divided into three models: nominal, specification and verification surface model. Expanded geometrical features exist in three “worlds”: nominal, specification and verification worlds. Operations are specific mathematical tools to obtain ideal or non-ideal features, or values of characteristics, their nominal value and their limit(s). The operations used to define the specifications can be divided into seven classes: partition, extraction, filtration, association, collection, construction, and evaluation. With a simple mechanism as an example, the geometrical expression specifications for the functions, design, manufacture and verification of a product are illustrated.     

任意转角位置的双圆弧齿轮的齿廓数学模型

在基于加工原理及渐开线展开原理的基础上建立的任意转角位置的双圆弧齿轮齿廓数学模型，其表述简单，应用时无须作坐标变换，能准确、真实地描述双圆弧齿轮轮齿在任意转角位置时齿廓上的任一点，实现子登粤弧齿轮齿廓的简单、准确、快捷计算，为双圆弧齿轮数字化设计、制造、啮合分析、运动学和动力学分析提供了简单、快捷的新理论依据。     

切削Ti -6Al -4V硬质合金涂层平头立铣刀的几何参数优化仿真研究

Ti - 6Al - 4V具有热导率低、弹性模量低、加工硬化严重及化学活性高等特点,属难加工材料,一般采用涂层硬质合金刀具加工.刀具几何参数对切削力、切削热、加工表面质量有重要影响.对刀具几何参数优化能够获得最优的刀具切削性能.使用有限元分析软件AdvantEdge建立三维立铣模型,采用单因素试验法模拟分析TiCN/A...     

Mathematical model and tooth surfaces of recess action worm gears with double-depth teeth

In this study, the surface equations of recess action (RA) worm gears with double-depth teeth, generated by a ZN worm-type hob cutter, are proposed. Based on the generation mechanism and the theory of gearing, a mathematical model of a series of worm gears, semi RA, full RA and standard proportional tooth types, with double-depth teeth is developed as the function of design parameters of the ZN worm-type hob cutter. According to the derived tooth surface equations, computer graphs of a series of worm gears with double-depth teeth are plotted. Tooth surface variations of the generated RA worm gears due to the varying pitch line, pressure angle and tooth height of the hob cutter are also investigated.     

3-PSS并联机构正解及其在坐标测量机中的应用

针对传统坐标测量机和关节臂测量机存在的技术局限,基于3-PSS并联机构原理,提出了只需一只长光栅、一条精密导轨即可实现三维空间精密测量的坐标测量机,并研究了测量系统的测量模型、测量误差模型及并联机构误差平均效应.根据并联机构基本理论建立了测量机的六杆测量模型,在此基础上进行了杆长制造、装配误差和光栅读数误差的理论分析.然后,从理论上展示和说明了并联机构存在误差平均效应的数学本质和依据.最后,介绍了样机的设计及制造,并给出初步的实验结果.在没有进行误差修正和系统标定的前提下,该样机在X,Y,Z3个坐标方向上的测量误差分别为0.029 mm,0.045 mm和0.058 mm.得到的结果可指导新样机的优化设计.     

再制造公差设计优化模型及其应用

为降低再制造产品的成本,保证和提高产品质量,将公差设计方法引入再制造工程。在深入分析再制造公差设计特点和公差分配原则的基础上,提出了一个再制造公差设计的优化数学模型。该模型以统计公差原理为基础,以再制造总成本最低为目标,综合考虑了保证和提高产品性能、表面工程技术、过程能力指数等制约因素,在质量成本中的田口质量损失成本的基础上增加了质量保证成本。结合某企业ZQDR-410型牵引电动机的再制造案例,对传统再制造方案和所提方案进行了比较,证明了该公差设计优化模型的有效性和实用性。     

改进蜂群算法在平面度误差评定中的应用

为了准确快速评定平面度误差,提出将改进人工蜂群( MABC)算法用于平面度误差最小区域的评定.介绍了评定平面度误差的最小包容区域法及判别准则,并给出符合最小区域条件的平面度误差评定数学模型.叙述了MABC算法,该算法在基本人工蜂群算法( ABC)模型的基础上引入两个牵引蜂和禁忌搜索策略.阐述了算法的实现步骤,通过分析选用两个经典测试函数验证了MABC算法的有效性.最后,应用MABC算法对平面度误差进行评定,其计算结果符合最小条件.对一组测量数据的评定显示,MABC算法经过0.436 s可找到最优平面,比ABC算法节省0.411 s,其计算结果比最小二乘法和遗传算法的评定结果分别小18.03μm和6.13 μm.对由三坐标机测得的5组实例同样显示,MABC算法的计算精度比遗传算法和粒子群算法更有优势,最大相差0.9 μm.实验结果表明,MABC算法在优化效率、求解质量和稳定性上优于ABC算法,计算精度优于最小二乘法、遗传算法和粒子群算法,适用于形位误差测量仪器及三坐标测量机.     

任意转角位置的双渐开线齿轮的齿面数学模型

运用渐开线展开和曲线包络原理,建立了双渐开线齿轮端面齿廓数学模型,用数据验证了模型的准确性。在端面齿廓数学模型基础上建立了任意转角位置的双渐开线齿轮齿面数学模型,使用该模型获得了三种典型刀具齿顶圆弧半径的双渐开线齿轮三维仿真图形,并进行了啮合仿真,从而验证了齿面数学模型的正确性和可行性。该齿面数学模型表述简单,使用时无须坐标变换,能快速、真实地描述双渐开线齿轮任一轮齿在任意转角位置时齿面上的任一点。为双渐开线齿轮三维数字化设计、制造,啮合干涉、运动学和动力学分析提供了简捷的新理论依据。     

Evaluation model for multi-process capabilities of stranded wire

Stranded wire is the most important component of familiar mechanical equipment such as elevators, cable cars, and cranes. The quality of these products that are used on a daily basis are mainly affected by the tensile strength of stranded wire. In order to attain the purpose of economical design and a long life span of stranded wire, a less relaxation property of strand type is suitable for manufactured tools. Thus, the manufacturing industries of stranded wire need to reach the goals of high tensile strength and low relaxation. To ensure the required quality of stranded wire, the strand pull test and the long period relaxation test are two important quality assurance tests. There are three specific items of the tensile strength test that belong to the larger-the-better quality type. The quality type of the smaller-the-better is for the long period relaxation test. However, many existing methods are able to measure process capability for the product with a single quality characteristic although it cannot be applied to most products with multiple properties. Thus, the indices of C_pu and C_pl, for the larger-the-better and the smaller-the-better quality type respectively proposed by Kane [5], are quoted and combined to propose a new index to evaluate the quality of multiple characteristics of stranded wire in this article. The principle of statistics is then used to derive the one-to-one mathematical relationship of this new index and ratio of satisfactory production process. Finally, the procedure and criteria to evaluate the quality of stranded wire is proposed. This integrated multi-quality property capability analysis model can be used to evaluate the multi-process capabilities and provide continuous improvements on the manufacturing process of stranded wire.     

齿轮形超硬修磨轮的设计与制作技术

论述了齿轮形超硬修磨轮的制造工艺 ,提出了基体轮的设计原则 ,分析了主要工序的技术要求 ,研制出了高质量的齿轮形超硬修磨轮 ,并用于对齿轮加工刀具和砂轮的修形上 ,为硬齿面齿轮多种高效精加工方法的应用提供了保证。     

Measurement uncertainty evaluation of conicity error inspected on CMM

The cone is widely used in mechanical design for rotation, centering and fixing. Whether the conicity error can be measured and evaluated accurately will directly influence its assembly accuracy and working performance. According to the new generation geometrical product specification(GPS), the error and its measurement uncertainty should be evaluated together. The mathematical model of the minimum zone conicity error is established and an improved immune evolutionary algorithm(IIEA) is proposed to search for the conicity error. In the IIEA, initial antibodies are firstly generated by using quasi-random sequences and two kinds of affinities are calculated. Then, each antibody clone is generated and they are self-adaptively mutated so as to maintain diversity. Similar antibody is suppressed and new random antibody is generated. Because the mathematical model of conicity error is strongly nonlinear and the input quantities are not independent, it is difficult to use Guide to the expression of uncertainty in the measurement(GUM) method to evaluate measurement uncertainty. Adaptive Monte Carlo method(AMCM) is proposed to estimate measurement uncertainty in which the number of Monte Carlo trials is selected adaptively and the quality of the numerical results is directly controlled. The cone parts was machined on lathe CK6140 and measured on Miracle NC 454 Coordinate Measuring Machine(CMM). The experiment results confirm that the proposed method not only can search for the approximate solution of the minimum zone conicity error(MZCE) rapidly and precisely, but also can evaluate measurement uncertainty and give control variables with an expected numerical tolerance. The conicity errors computed by the proposed method are 20%-40% less than those computed by NC454 CMM software and the evaluation accuracy improves significantly.     

Modelling, Implementation, and Manufacturing of Spiral Bevel Gears with Crown

The operational performance of gears in terms of smoothness, quietness, wear and life span is largely affected by how gear and pinion teeth make contact. To enhance the operational performance, a crown is often applied to a standard (nominal) gear tooth surface. Regardless of the presence of a crown, all the gears are machined by special types of machine tools, such as gear hobbers and shapers. This paper develops a tooth surface for a spiral bevel gear with a crown so that it can be machined by numerically controlled machine tools. Specifically, we derived: 1. A bi-parametric tooth surface model for a standard spiral bevel gear. 2. A crown model along the spiral curve direction. 3. A crown model along the involute curve direction. The developed algorithm was tested and implemented in a prototype software system called GearCAM. With the GearCAM system, a set of spiral bevel gear and pinion was machined using a 4-axis CNC milling machine to check the validity and effectiveness of the crowning method. Through various verifications, it is shown that the models developed for the standard and crown gears can be used as a means for design and verification of spiral bevel gears.